Vulgar half-couple acquire a legume (7)

I believe the answer is:

plebean

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'vulgar' is the definition.
I know nothing about this answer so I can't judge whether this works.

'half-couple acquire a legume' is the wordplay.
'half' indicates taking half.
'acquire a legume' becomes 'bean' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'couple' cut in half is 'ple'.
'ple'+'bean'='PLEBEAN'

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I've seen this clue in the Sydney Morning Herald.

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